Clean hands can lead to an explosive detection test

Letter from a reader who’d had an unfortunate experience at Dubai Airport.

Reboarding her Qantas flight she was selected for an explosive detection test and came up red! Retested, same thing again. Taken to a secure area where all her belongings were thoroughly searched, passport photographed, almost missed her flight.

Nothing untoward found – but was it possible that antibacterial hand wash she’d used had set the machine off?

Answer: yes. Moisturisers, hand sanitisers, detergents, air fresheners and even soap are just some of the products that will likely contain glycerin and this is one of the substances that explosive detection devices are programmed to scan for. No big deal – security personnel should be aware there are many products that can falsely trigger a red alert but that pose no danger, but you can expect to be grilled. Explosive detection devices are designed to sniff out the most minute traces of substances that could be used to make a bomb. Glycerin is a natural by-product of the soapmaking process but it‘s also a component of nitroglycerin, used to make dynamite – pow!

For the authorities charged with maintaining airport security the rationale is that it is much better to have a high rate of false positives – innocent travellers who record a positive reading – than run the risk of false negatives – travellers who might have been exposed to, or are transporting an explosive substance, and who might pass undetected.